Re: [OctDev] convhulln =?iso-8859-1?Q?opti?= =?iso-8859-1?Q?ons=2E_=BFDo?= we need a better implementation?

[Rafael L. <rla...@us...>]

* Pedro Tarrafeta <pt...@te...> [2003-11-21 16:36]:

> This is a post to start discussing the convhulln implementation in octave.
> 
> convhulln() is a function that returns the convex hull of a set of points. It 
> is based on qhull (http://www.thesa.com/software/qhull/).
> 
> Lets start with an example to center the discussion.
> I did prepare the following script:
> 
> [...]

Thanks for this thorough example. 

> If we run it with QJ or Qt options we get triangulated output, although the 
> triangulation is different.
> 
> So... after writing this long, long brick.... Should we give some more 
> functionality to the convhulln function? (maybe giving it some other name
> for compatibility reasons). I don't understand why the new convhulln
> doesn't give also triangulated output (not trimmed rows...).

My understanding is that Paul Kienzle fixed this problem in his last commit
to convhulln.cc, namely by adding a Qt option to the qhull command call.

More than one year ago I changed the delaunay3.m, delaunay.m, and
delaunayn.cc files such that the associated functions would accept an extra
(optional) argument containing additional options to the qhull command.
This extra argument is just a string that is concatenated to the qhull
command string.

I think that a similar change to convhulln.cc would fit your needs.  Also,
similar changes could be done to the voronoy functions.  Should I implement
them?

-- 
Rafael